Phonograph-record-rotating mechanism



- July 3, 192a.

I A. pm'nosou PHONOGRAPH RECORD ROTATING MECHANISM 2 Sheets-Sheet Fi1ed March 17,

\mxfi I WW LEX Rov DAVIDSON INVEN TOR.

A TTORNEY Jlfly 3, 1928. 1,675,697

A. R. DAVIDSON PHONOGRAPH RECQRD ROTATING MECHANISM Filed March 17, 1926 2.Sheets-Sheet 2 INVENTOR.

) v ALEX RoY DAVIDSON r I I W ATTORNEY;

Patented July 3, 1928.

annxnnnnn nox-toavmson, or nnMoNTon, Anagram, CANADA.

rnonoemnr-nnconntnorarme nncnamsra Application met 17, 19a, senain 95,4;14, and m Canada Fehrnary24, 19,26,

My present invent on appertains generally to improvements in the art of, sound rep-r0 ducing instrumentalities, and specifically to phonograph record rotating; inec ian i sm pro viding accelerating rotation and, uniform speed ot'gtravel off, the record, soundgroove past the tone arm stylus, as descrihejd in the present,specification and illustratedfln. the, accompanying drawings.

In phonographs and disc record is rotated, at uniform speed.

Therefore, a, Il-ZCQI'QI: is played, tlieQSpead' of travel oftheidisc record sounchgroove past the tone arm gradually, decreases, In, consequence of which the-number of. notes which may be playeddfrom a recordis yery limited. V i

To obviate this, I propose, 1n, the manufactur ng oisthe records, ton'otate the same so as to provide L1,,11Illf0l'lILSPtQCl,Of travel;

ofthe sound groove past, the saidstylus, and, in the playing ofi the, record on tie sound reproducing instrument, to gradually accelcrate theplayingfrecord to provide uniform speed ot-travel of the sound groove past the reproducing tone arm to harpidnifm, withrthe record, By do ng th1s, the volume,

of notes whicli nayibe playe liirqm a rgeord tl will be greatly increased, inthahwlie i the record is beingproduced and played, an fthe stylus is seated in, a sound groove nea ythe periphery of the record, the record is ro tated at the required speedgtmmaheyandplay the notes. As the spiral sounn" i=edves"become smaller in diameter, this speed of rotation of the record is proportionately increased to provide a uniforms eed of travel of the said groove past the sty us.

This invention has to do particular] with the reproducing instrument for p. aying records manufactured as above noted, and has for its object the provision of reproducing mechanism comprising, in combination with record rotating means and a tonearm, of means interconnecting the same, so that when a record is being played and the tone arm moves thereacross, the speed governing means is released to increase the speed of rotation of the record in unison, thus providing a uniform speed of travel of the sound groove past the tone arm stylus throughout the playing period of the record.

The invention is further characterized by the provision of means for adjustin said interconnecting means to vary the p aying [of-the present, applicatiomandin which: v. v FW ep ucin v instruments ottliis character, the,play ng speed of the ,lnstllllllltilllt as occasion! demands,

description proceec s, the V invention 6c in the novel combination and arrangement of co-operating elements as, hereinafter more specifically set forth, 1 cla med, and shown v m the accompanying drawings formin apart invention. i p a Fig. 2 1s a, i'ragn'ientary detail View, showc the p aoa ae s era an p edi ae trol, and H I l l Eng. 3 1s a similar VIEW, shogving the gov:

ernor and speed controliri another, positTon.

Like i'iumerals 01 reference designate cor- 7. .2

responding components, throughout the severalv ews'. c y

'llhemnncral 4t designates the cabinet of phonograph ingcnerah which prpvidech with the usualdetachablecover section 5L8! A toncf arin 6, carrying the,sound reproducQ ing box'i and stylus 8, is pivoted, in the usual manner to tlie base plate 9. desig, jnates the sonndbox. H 'llherpcord,platedrivng mechanism may, for, Illustration, purposes, comprise the sprin motor,designated at 11, in its, entirety, whic i dri ves the record plate rotating spiralgcar 12, the speed of whichdis controlled by the conventional, governor 13.

My invention resides in the interconnecting of the tone arm 6 with the governor 13 to increase the speed of the latter, and incidentally the record plate, during the playing period of the record, to provide uniform speed of travel of the record sound groove past the stylus 8.

An acceptable form in which my invention may be carried into practice, may comprise a crank rod 14: keyed to the elbow of 1 the tone arm 6 and extended vertically axially therethrough, the lower end of which is supported in the boss 15 on the sound box 10. A crank 16 is formed on this rod near its lower end. may be supported in the bracket 17 carried by the base plate 9, if required.

' Connected to the crank aforesaid, and ex tended horizontally through the sound box 10, is a connecting rod 18, one end of which is pivoted to the extremity of the rod 19, as at 20. This rod 19 extends through the The upper end of said rod 6 sound box 10 and longitudinally along the top thereof, being supported in the bearing 21. The other end of this rod is bent u)- wardly, and is connected as at 22 to t e governor speed controlling lever 23.

This governor speed controlling lever 23 is pivoted as at 24 to the end of the slide 25, which is slidably supported by the extension 26 on the motor base casting 27. This slide is adjusted lon itudinally by the adjusting arm 28, pivotet thereto as at .29 and fulcrumed to the extension 30 of the motor base casting 27, as at 31. The up er end of the adjusting arm extends throug a slot in the cabinet cover section In Fig. 1, I have shown the position of the components of the mechanism when the instrument is in starting position. In this position, the governor 13 is regulated for slow speed. As a record is played, the tone.

arm 6 swings across the record toward its centre, which action gradually turns the rod 14 and moves the rod 19 in the direction indicated by the arrow at thus releasing the governor from the position indicated by the line AB, (Fig. 2), which indicates the starting position, and permitting the same to gradually accelerate the record plate and record to provide uniform speed of travel of the record sound groove past the tone arm stylus. When the record has been fully played, the governor may have extended to the position indicated by the line C-D. dependent upon the size of the record. \Vhen the motor 11 is stopped, the governor 1.1 recedes to the position shown in Fig. 1,'permitting the tone arm to be swung across the record to starting position. i

It is obviously necessary to provide a speed control, to adjust the speed of the governor to accord with the various selections played. This is provided by mounting the lever 23 on the adjustable slide 25,

means; a governor therefor; a speed control forsaid governor; a laterally swinging tone arm; a rod extending vertically through the pivotal axis of said tone arm and engaged to turn therewith; the lower end of said rod being bent in crank formation; a connecting rod reciprocallymqunted and having one end connected to said control; a second connecting rod having one end ivotally connected to the first -mentione connecting rod and its other endconnected to said crank formation.

2. In combination, record plate rotating means; a governor therefor; a speed control for said governor; a laterally swinging tone arm; a rod extending'vertically through the pivotal axis of said tone arm and engaged to turn therewith; the lower end of said rod being bent in crank formation; a connecting rod reciprocally mounted and having one end connected to said control; a second connecting rod having one end pivotally connected to the first mentioned connecting rod and its other end connected to said crank formation; said speed control being fulg crumed on a slide member and a means for reciprocating said slide member.

In testimony whereof, Iaflix my signature.

ALEXANDER ROY DAVIDSON. V 

